Virus resistant plants

Abstract

An isolated DNA sequence which codes for a potyvirus replicase gene is disclosed herein. A method for providing resistance to infection by a virus by expressing a replicase gene in plants is also disclosed. Transgenic potato plants and tubers containing the replicase gene are also disclosed.

We claim: 
     
       1. A DNA molecule which comprises in the 5' to 3' direction: (a) a promoter region which functions in plant cells to cause the production of an RNA sequence, operably linked to   (b) a structural gene encoding a full-length potato virus Y (PVY) replicase, operably linked to   (c) a 3' non-translated DNA sequence which functions in plant cells to cause the termination of transcription and the addition of polyadenylated ribonucleotides to the 3' end of the transcribed mRNA sequence.   
     
     
       2. A DNA molecule according to claim 1 wherein said promoter region is selected from the group consisting of FMV promoter regions, CaMV35S promoter regions, and enhanced CaMV35S promoter regions. 
     
     
       3. A DNA molecule according to claim 1 wherein said promoter region is the FMV promoter region of SEQ ID NO. 4. 
     
     
       4. A DNA molecule according to claim 1 wherein said structural gene is SEQ ID NO. 1. 
     
     
       5. A DNA molecule according to claim 1 wherein said 3' non-translated region is selected from the group consisting of nopaline synthase (NOS) genes, soybean 7S storage protein genes, and small subunit of the ribulose 1,5-bisphosphate carboxylase-oxygenase (ssRUBISCO) genes. 
     
     
       6. A DNA molecule according to claim 1 wherein said 3' non-translated region is from the pea small subunit of the ribulose 1,5-bisphosphate carboxylase-oxygenase (ssRUBISCO) E9 gene. 
     
     
       7. A method for providing resistance to infection by potato virus Y (PVY) in a susceptible Solanaceous plant which comprises: (a) transforming plant cells with a DNA molecule encoding a full-length replicase from a PVY isolate which is capable of infecting said plant;   (b) regenerating said plant cells to provide a differentiated plant; and   (c) selecting a transformed plant which expresses the PVY replicase gene at a level sufficient to render the plant resistant to infection by said PVY isolate.   
     
     
       8. A method according to claim 7 wherein said plant is selected from the group consisting of potato, tomato, and tobacco. 
     
     
       9. A method according to claim 8 wherein said potato is a variety selected from the group consisting of Russet Burbank, Shepody, Atlantic, Norchip, and Superior. 
     
     
       10. A method according to claim 9 wherein said potato variety is Russet Burbank. 
     
     
       11. A DNA molecule which comprises in the 5' to 3' direction: (a) a promoter region which functions in plant cells to cause the production of an RNA sequence operably linked to   (b) a structural gene encoding SEQ ID NO. 1 operably linked to   (c) a 3' non-translated DNA sequence which functions in plant cells to cause the termination of transcription and the addition of polyadenylated ribonucleotides to the 3' end of the transcribed mRNA sequence.   
     
     
       12. A method for providing resistance to infection by potato virus Y (PVY) in a susceptible Solanaceous plant which comprises: (a) transforming plant cells with a DNA molecule encoding SEQ ID NO. 1;   (b) regenerating said plant cells to provide a differentiated plant; and   (c) selecting a transformed plant which expresses SEQ ID NO. 1 at a level sufficient to render the plant resistant to infection by PVY.   
     
     
       13. A stably transformed, viral resistant Solanaceous plant which contains in its genome a DNA molecule of and of claims 1-4.